Apparatus for winding artificial silk for treatment



w. F. RICHTER 1,957,979 APPARATUS FOR WINDING ARTIFICIAL SILK' FOR TREATMENT May 8, 1934.

Filed March 21, 1951 4 Sheets-Sheet 1 INVENTOR wrmessas May 8, 1934.

w. F. RICHTER APPARATUS FOR WINDING ARTIFICIAL SILK FOR TREATMENT Filed March 2l 1931 4 Sheets-Sheet 2 wn-ussses May 8, 1934. 1,957,979

' APPARATUS FOR WINDING ARTIFICIAL SILK FOR TREATMENT w. F. RICHTER 4 Sheets-She et 3 Filed March 21, 1931 INVENTOR K FIN/5H y 1934- I w. F. RICHTER 1,957,979

APPARATUS FOR WINDING ARTIFICIAL SILK FOR TREATMENT Filed March 21, 195i 4 Sheets-Sheet 4 '6 ma the foramina i a tented May 8, 4

AP ARATUS FOR WINDING ARTIFICIAL SILKLFOR TREATMENT William F.

. corporation of Delaware Richter, Apollo, Pa., assignor to Chemical Holding Corporation,

Apollo, Pa.,v a

Application; March 21, 1931, SerialNo. 524,407

7 Claims. (Cl. 242-'43) This invention relates generally to mechanism for winding filaments intended for textile use, and particularlyto a device for guiding a thread of filaments to form a body or cake of shape adapted to facilitate subsequent treatment of the thread. a A It is among the objects of my invention to provide mechanism for winding or laying up thread in predetermined shape, that is simple in construction and rugged in operation. l

Another object of my invention is to provide mechanism for winding rayon thread on forami; nous drums in such manner that fluids utilized in treating the rayon may be distributed from uniformly through the cake to effect uniform treatment of the entire cake. to effect economies in the amount of fluid required, to shorten the time necessary for treatment, and with minimum damage to the thread. I 20 A further object is to-provide a winding device for laying up thread in a cake having a cylindrical mid-portion and convexly'rounded end portions adapted to provide substantiallyuniforni liquid permeability from end to end. I The apparatus provided by this invention comprises a drum having a foraminous mid-portion for receiving thread, and a guiding mechanism for laying up the thread on the drum, controlled to form a cake. having a cylindrical mid-portion covering the foraminated portion of the drum, and convexly rounded end portions extending beyond the foraminated portion, the thread being so laid that all partsorthe cake are. uniformly .pervious to fluids passed through the foramina from the interiorof the drum. Cakes wound in this manner may be speedily and uniformly treated, as by washing with water or with other treating fluids that may be introduced into the drum' and permitted to pass outwardly by. gravity' through the cake while the drum'is rotated slowly One type my invention, to achieve the foregoing and other objects thereof that will be more readily apparent upon reading this specification, is described of specific apparatus for practicing in detail hereinafter in conjunction with the accorhpanying drawings. In the drawings-Fig. 1 is a front elevation of a conventional rayon spinning machine, some parts being broken. away to better show the winding mechanism which mbodies my invention; view of the apparatus shown in Fig. 1, showing on an enlarged'scale the traverse, mechanism, parts being broken away for clarity of illustration; Fig. 2 is an end elevation of the mechanism theprimary cam during 0 -8 is a diagram similar to Fig. I

' revolution thereof.

- mind'that the spinning apparatus is shown for Fig. 1a is a fragmentary.

showing diagrammatically the. sectional shapes similar to Fig. 3 showing in is of the type adapted to to adapt them to shown in Fig. 1, with the winding mechanism similarly exposed; Fig. .3 is an enlarged longitudinal section of a portion of the-winding drum of cakes formed by single cam winding mechanisms of different types; Fig. 4 is a view similar to Fig. 3 showing cakes formed by winding mechanisms having compound cams; Fig. bis 2. view detail a section of the foraminous winding surface of the drum and a cake of rayon thread laid thereon in accordance with my invention; Fig. 6 is a'developmentgrepa resenting the winding surface of the drum and illustrating the manner in which the thread is wound thereon; Fig. 7 is-a diagram showing the motion imparted to the winding mechanism by r e revolution; and Fig.

showing the moduring one tion imparted by thesecondary cam 7 The particular spinning apparatus shown in the drawings and described in this specification produce rayon by the viscose process. However, it should be borne in purposes of illustration only, and that the winding mechanism which embodies my present invention may be applied to any type of spinning or other mechanism from which it may be desirable towind thread in cakes of uniform permeability subsequent treatment/ into the details of construction Without going 'ofthe spinning apparatus shown in the drawings,

it comprises in general a framework 1 upon which is supported a tank 2 containing a precipitating; or coagulating bath 3 of suitable well known composition. A gear-type pump 4 forces viscose solution through a pipe 5 to a filtering device 6 from which it passes through a goose-neck 7 to a spinneret 8 beneath the surface of bath 3. The pump 4; is driven by a motor 9 through a suitable gear train 10 provided with a speed changing mechanism ll'for adjusting thespeed at which the pump operates, all of whichv mechanism is mounted in the frame 1 near the tank 2.'

.'I'lr1e filament-like. jets of viscose which issue from the spinneret 8 are coagulated by precipitatingbath 3 and are gathered together into a thread that passes over a guide member 15 on alongitudinally movable guide bar or traverse rod 16 m5 disposed above tank 2 in' suitable guides on frame 1. After passing over guide member 15 the thread is collected on the surface of a winding druml'? in what is known as a cake. The guide bar is placed as near to the drum as possible to 5 in which a plurality of spinnerets 8, connected to respective individual pumps 4, are suspended. Likewise guide bar 16 isprovided with a plurality of guide members 15, in this case five, for guiding thread to five winding surfaces 18, separated by.

flanges 19, on drum 17, .whichis rotatably supported in frame 1 by movable heads or clutching elements 21.

After the cakes have been formed upon the drum the movable heads 21 may be withdrawn by means of fluid pressure devices 22 to release the drum for removal and replacement by an empty drum. .As shown, one of the movable heads 21 is connected by a suitable driving mechanism 23 to the speed changing mechanism 11 driven by motor 9 in such manner that the drum is rotatedat a speed corresponding with the speed at which the viscose solution is delivered to the spinnerets 8.

The particular method of collecting and treating rayon thread upon the drum, and the details of its construction, are more fully set forth and claimed in my copending application Serial No. 505,749, filed December 31, 1930. As described in this copending application, the drum preferably is a cylinder of relatively thin metal provided with outwardly pressed flanges '19 which form individual winding surfaces 18. The drum is completely covered by a protective coating 25, for example rubber. As best shown in Fig. 5 the protective coating is molded to form cup-like depressions 26 in the midportions of the winding'surfaces 18 each of which leads to and is concentric with one of a plurality of foramina 2'7 in the drum.

After a cake 28 of rayon has been' formed on drum 17, water or other treating liquid is intro fduced into the drum, as more fully explaineddn the aforementioned copending application, and permitted to seep through the cake 28 as it issues from the interior of the drum through the foramina 27. Inasmuch as the freshly spun rayon yarn in cake 28 is very delicate, the liquid must be passed through it at low pressure to avoid breaking the filaments. In accordance with the invention of the copending application, treatment is accomplished with minimum damage to the thradby allowing the treating liquid to seep through the form'ania under its static-pressure head only. Satisfatory results are had ordinarily by filling the drum to about '75 per cent of its capacity. To provide for treating all portions of the cake equally, drum 17 is rotated atza slow speed, usually about fifteen revolutions per minute, preferably in the direction in which the thread was wound on it.

In order to effectively and expeditiously treat the yarn, the cake must be wound on the drum in such manner that the treating liquid may pass freely through it, but so that all portions of the cake will oifer substantially equal resistance to the flow of the treating liquid. That is,'- each portion of the cake must come in contact with a predetermined amount of treating fiuid, and no ,portion should be shaped to permit the passage of an'excessive amount of fluid, nor, conversely, should any portion be so wound or positioned'that little or no fluid comes in contact with it. For instance, the edges of cake 28 should not be wound against partitions 19, as is the usual practice in winding thread on spools, inasmuch as the threads adjacent to the partition would not be exposed to the treating fluids. Consequently, the edges of the cake must be free from the partitions, and be self-supporting. Further, the self-supporting edges must be so wound' that the individual threads of rayon will retain their original positions during subsequent handling and treating operations to avoid tangling, which would be troublesome when the thread islater' unwound from the drum.

This invention provides means for laying thread in a cake in such manner as to confer the foregoing qualities.

The optimum shape of the cake provided .by the invention is shown in longitudinal section in Fig. 5.' The cake is wound, inac-' cordance with my invention, with a substantial-' ly' cylindrical mid-portion of width substantially equal to the width of the foraminous portion of winding surface 18, and with its end portions extending beyond the marginal foramina of 'the winding surface and convexly rounded. When wound in this shape the'cake is self-supporting with the end portions so formed that the individualthreads will not slip over one another and tangle during subsequent treatment.

The surface of the rounded end portions is at all points so spaced from' the marginal foramina that the resistance to liquid flow from the foramina through the end portions is substantially' uniform and is substantially equal to the resistance to flow through the cylindrical mid-portion of the cake. Inasmuch as there is less tendency for the treating fluid to flow horizontally than vertically through the cake, the

extreme edge of the curved end portion is dis posed relative to the marginal foramina at a distance less than the thickness of the cylindrical portion of the cake to compensate for this -condi-' tion and provide uniform liquid permeability. Consequently, all portions of the cake are substantially equally pervious to liquids issuing from the foramina 27, and each turn of the rayon thread will'be exposed to a substantially equal amount of the treating fluids. Further, after the cake has been suitably treated, the thread may be unpound from the drum 17 without difficulty.

This invention provides mechanism for moving the traverse rod or guide bar 16 longitudinally to cause the individual guide members 15 to move back and forth across the respective winding surfaces 18 of drum 17 with a cyclic non-uniform motion in such manner that cake 28 is laid up to the desired shape with the threads crossing each other toprovide passageways between them for the treating fluids.

The mechanism for moving guide bar 16 is carried in a cabinet 30 at the side of frame 1 It comprises a rotatably mounted primary cam 31 .of constant diameter that engages a pair of cam followers 32 on a crosshead 33, slidingly mounted in the cabinet, to which is pivoted one end of an operating lever 34. The lever 34 is pivoted at its other end toone end of guide bar 16 and is fulcrumed on a second movable crosshead 35, mounted in cabinet 30 to slide parallel to crosshead 33, at a position about one-fourth of the length of the lever from its point of pivotal connection to crosshead 33. A suitable motor 36 is provided on the top of frame 1 for driving cam 31, and is connected to it by a suitable speed changing mechanism 37 and a chain and sprocket wheel drive mechanism 38.

To more readily understand the manner in which the optimum shape for the cake is attained, it is desirable to. consider the results to beobfulcrum crosshead 35 held stationaryyand with harmonic motion guide bar 16 moves slowly at ends of the cake.

motionimparted to guide bar 16 during the mid-- portion of its travel by the harmonic cam, a pro-f cams of various well known shapes utilized in the position occupied by primary cam 31. In the event that cam 31 is; shaped to give a'simple harmonic motion to guide bar 16, av cake of the form indicated by the-"dotted line A in Fig. 3 would be formed. The'high humps at the edges of the winding A result from the fact that with a simple the end positions of its travel. 'This permits an excessive amount of thread to be wound at the Likewise, because of the rapid nounced depression'is .formed at the mid portion of the winding A. t t

The humps at the edges of the winding are fur ther accentuated by reason of the fact that the thread does not follow the guide bar at once when it changes direction of motion. In order thatthe edges of the cake may be self-supporting, and to form a honey-combed cake that is pervious L to fluids, guide bar 16. must be moved back and forth with suificientrapidity to lay thethread on the drum angularly. In changing from an angular lay in one direction to anangular lay in the other direction the rayon thread must necessarily lay substantially circumferentially at the end portions of the cake. The guide bar 16 must then move some distance away from the endposition before the efiect of its movement will cause the thread to change from its circumferential position to an angular lay in the new direction. Consequently more thicknesses of thread are applied at the ends of the cakethan at other portions. I a If'cam 31 has straight line or uniform motion characteristics, theobjectionablefeatures of the harmonic motion will-be overcome, but the yarn continue to pile up in a hump at the ends as shown by the'dotted line B, because of the lag j in responding to the change in direction of the guide bar. Because of the accumulation of yarn at the end portions of the cake B, the center or mid-portion is depressed, but to an extent somewhat less than the depression found at the midportion of the cake A. i

By suitably proportioning cam 31 to give a motion to guide rfod 16 that may be termed-an inverse harmonic motion, that is motion .which is rapid at the ends of the stroke and slow at the mid-portion of the stroke, the depression at the "d-portion of the cake may be substantially reduced. This is shown by the full line C in Fig.

3. However, it'has been found to be impossible by means of a single cam to form a cake that has the desirable characteristics of cake 28, Fig. 5. To reduce or distribute the-humps formed at the ends of the winding as a result of the reversal of the guide at this point, I have developed".

mechanism for shifting the range of travel of the guide bar 16. This mechanism utilizes primary.

cam 31 of the most desirable shape, which by itself gives an inverse harmonic motion to guide bar 16 and forms a cake indicated by C in Fig.

i 3, and it cooperates with a secondary cam 41. The

' secondary cam engages a pair of cam followers 42 oncrosshead 35 that serves as a fulcrum for operating lever 34.

The diameters of the cams 31 and 41' and the lengths of the lever arms with'which they move guide bar 16 are such that cam 31 is capable of moving the guide bar through substantially 85% of its total range of travel, and cam 41, if acting alone. would move the guide bar through substantially 15% of its total range of travel. Thus, it both cams were turned simultaneously and in operates cam41 at a speed somewhat phase, guide bar 16 would be caused to ,move over the entire range of its travel. If, on the other hand, the cams 31 and 41- were operated in synchronism and 180 would move through only of its total range of movement. In the mechanism shown, the cams 31 and 41 are interconnected by a gear train which I more than one-fourth of the speed'of cam 31. The gear train referred to, comprises a gear 43 mounted on the shaft'carrying cam 41, and it is driven by a out of phase, guide bar-16- pinion 43a keyed on' the shaft which carries sprocket wheel 38a and cam 31, as shown especially in Fig. la. "Consequently the phase relation of the cams changes continuously in such manner that the actual length of stroke of rod 16 is approximately of its total range of movement.' Further, the range of action shifts back and forth across thewinding surface of the drum as the 'phase relation of the cams changes,

in a manner presently to be explained more fully.'

If cam 41 is of'the plain eccentric type. it wi l shift the range of action 'of the guide rod 16 in such manner that the winding is distributed in accordance with the dotted-line D in 4. As shown, the motion given to guide rod 16by the cooperative action of inverse harmonic cam 31 and an eccentric or harmonic cam", 41 results in a cake having practically no hum ps'at its end portions and with the mid-portion filled to substantially cylindrical shape. However, the end portions of thecake *B are not in suitable shape to provide for uniform treatment of the rayon, inasmuch as they are concave and the concave portions do not offer sufficient resistance to the flow of liquid thereby permitting an excess of l treating fluidto pass through between the threads trated bythe cake 28 of optimum shape shown in Fig. 5.

The characteristics of the particular cams 31 and 41 which in combination have been found to produce the optimum form of cake are shown. in the diagrams in Figs. '7 and 8, respectively.

,From the curves there shown, it may be seen that ...the cams 31 and 41 each. impart to the guide bar a cyclic motiomthat is slower in the mid-portion of. the travel than at the end portions. The resulting motion which the cams 31 and 41 acting If now secondary cam 41 isshaped to have* togetherimpose'upon the guide bar is, of course,

- different from that imparted by either cam, and

also d'fierent from the sum of the motions imparted by the two cams, inasmuch as the phase relation between the cams changes continuously.

In a particular embodiment of my invention the total lengthof stroke through which the primary cam is capable of moving the guide rod 16is 6.5"inches. In this structure secondary cam 41 is capable of moving guide rod16 through a stroke of 1.06 inches. 7 gear train 43 connecting cam 31 and cam 41 is 42 -to 166, which is approximately a ratio of 1 The tooth ratio of the.

to 4, but with a slight variation of ratio to cause a continuous shifting of .the phase relation between the two cams. i

The relation between the speed of rotation of drum 17 and the speed at which the guide rod moves across the winding surface are not definitely interconnected in any way. However, in

the apparatus described the winding drum, which is sixteen inches in diameter, is rotated at sixtyfour revolutions per minute and the primary cam 31 is rotated at thirty-nine revolutions per minute.

In the developed layout of a few turns of thread on drum 17 shown in Fig. 6, the cycle oi operation may be traced throughfour revolutions of the primary cam 31, during which time the drum has turned about six andone-half revolutions. The various turns of the-thread on the drum are designated by the lower case letters a to g inclusive, the letters at each end of the diagram representingcorresponding points that have been arbitrarily chosen as the beginning of the particular turn designated by each of the letters respectively.

' If new we consider both .the primary and sec-- ondary cams -.to be at their extreme positions in one direction, guide 15 will beat the extreme end of its range of movement and the thread will be guided onto the drum toform the extreme edge J of cake 28, as indicated by the position S in the diagram. When one-half revolution of cam 31 has been completed, cam 41 will have made substantially one-eighth of a revolution, and the thread will have passed diagonally across the face of the winding surface to a position T that is at some distance from the other edgeK of the cake. At the end of one revolution of the primary-cam the thread will have moved back across the face of the drum to a position U which is not at the edge J ofthe winding, but is somewhat removed therefrom for the reason that cam 41 has in themeantime made approximately onefourth of a revolution. On the next half revolution of cam 31,-the thread is brought to the position V, somewhat closer to the edge K of the cake than it was at the position T, inasmuch as cam 41 has now made approximately threeeighths of a revolution. During the next half revolution-of the primary cam, that is at the end of the second revolution; the secondary cam has completed'approximately one half of a revolutionfso that the two cams are substantially 180 out of phase and the thread is placed at a position W which. is inwardly from the edge J of the cake a distance substantially equal to the width of the rounded end portion thereof.

At the end of the next half revolution of cam 31 the thread will be brought to the position X which is close to the edge K of cake 28, but is removed therefrom a short distance by reason of the fact that cam41 has by this time made substantially five-eighths of a revolution and cam 31 cannot coincide with it. At ,the completion of the third revolution of cam 31, thefsecondary cam will have made substantially three-fourths of a revolution, thus placing the thread at a position Y about midway between the starting position S and the inner position W.' The next half revolution of the primary ,cam will place the thread in position Z, which is removed a considerable distance from the other edge ,K ofthe winding, but does not define the extreme inneredge thereof, inasmuch as the cams 31 and 41 are not 180 out of phase at this point, secondary cam 41 having completed approximately seveneighths of a revolution. When primary cam 31 completes its fourth revolution, the secondary cam will have made slightly more than one complete revolution and the thread will lie at a position S1 that is not quite at the edge J of the cake, and that is removed angularly from the starting position S by an amount that depends upon the ratio of the speed of revolution of the drum to the speed of revolution of the cams.

At the end of eighty-three revolutions of cam '31, cam 41 will have turned exactly twentyone revolutions, Hence the cams 31 and 41 will pass through a position corresponding to the starting position, in which they are again in phase, and the thread will again be laid at the extreme outer edge J of the winding in a position corresponding to the initial position S. However, the

thread will, in all probability, not fall directly upon the position S, but will be removed angularly therefrom, inasmuch asthere is nodefinite synchronization between drum 17 and the cam mechanism.

In the meantime the other edge K of the cake '28, will have been defined, as the cams .31 and 41 will have synchronized with both cams in a position 180.from the position chosen as the starting'point. This will occur when cam 31 has made forty-one and one-half revolutions and cam 41 has made exactly )ten and one-half revolutions,;

laid at a posiat which time the thread will be tion on the extreme outer edge K of cake -28.

The inner edges of the rounded end portions,

or the division points between the end portions.

and the cylindrical midportions are defined by threads that are laid when the two earns 31 and 41 are approximately 180 out of phase. In the particular mechanism utilized to illustrate my invention, gear train 43 is so proportioned that the camshappen to be exactly in phase at the two posit'ions corresponding to theqextreme posi-' tions of travel of the guide bar 18, but they are not exactly-180 out of phase at the positions corresponding to the positions of guide bar 16 in forma'revolution. The other edgev of the cylindrical portion, adjacent to-ihe edge K, will be defined when cam 31 has made thirty-nine and one-half revolutions and cam 41 has made substantially ten revolutions. The thread laid when cam 31 has made forty-three and one-half revolutions and cam 41 has made substantially eleven revolu- 1, tions will also lie at the edge'K of the cylindrical portion. Likewise, when cam 31 has made eighty-one revolutions and cam 41 has made substantially twenty and one-half revolutions the thread will again lie at the edge of the cylindrical portion adjacent to theedge J.

Although for purposes of description I have chosena starting position in which the cams 31 and 41 are exactly in phase, it iszapparent that, in the operating view of the repeating nature of cycle, the winding operation may be started at any position. and without regard tothe particular relation of the cams. Likewise it is not necessary to start all of the spinning devices which furnish thread to the various winding surfaces at-the laced threads that. they reiain their shapes during subsequent treatment and may be readily unwound. Further, the cake is of. such open or honey comb structure with each thread separated from the others except at points where they cross, that an especially even distribution of treating fluids throughout the entire cake is obtained during the treating operations.

From the foregoing description of my spinning and winding apparatus; and the discussion of its mode of operation, it is apparent that I have invented apparatus for forming thread into cakes on a foraminated drum in such manner that all portions of the cake may be niformly washed or otherwise treated byfluid p ssed into it from the interior of the drum through the foramina.

It will be understood that the invention is not restricted to the particular application exemplified and described herein, but that it is applicable broadly to the winding of thread upon holders for subsequent treatment. For instance, it is equally applicable to the pot spinning process now commonly used in making viscose rayon. In such case the pot spun cakes are wound upon the drum in the manner described hereinabove, and the thus-wound thread is then treated or cured. A suitable mode of treating the thus-wound thread is that described in the aforesaid copending application.-

Although I have described one specific embodiment of my invention, giving particular proportions and. sizes of .parts which have been found suitable in practical operation, it is to be understood that this detailed discussion of my apparatus is merely for the purpose of accurately setting forth a practical embodiment thereof. It will'be apparent to others skilled in the art to which this invention relates that various modifications may be made in the sizesand proportions of the apparatus and in the general arr'angement of the parts involved without depart-. ing from the spirit and scope of this invention as defined in the appended claims.

I claim: e

1. In a rayon winding apparatus, the-combination with a winding drum and a movable guide disposed in working relation with the. drum of means for moving the guide to wind rayon upon said drum and comprising a primary cam, a secondary cam, and gearing positively interconnecting the cams to'cyclically change their phase relation, said cams and gearing coacting to wind the rayon angularly in intercrossing layers into a cake having a substantially cylindricalmidportion and convexly rounded end portions of radii less'than of the cake to provide a cake which is uniformly pervious throughout to treating fluids.

2..In a rayon winding apparatus the combination'with a rotatably mounted drum and a movable guide disposed in working relation with the drum, of means for moving the guide to wind rayon upon said drum and comprising a primary the thickness of the mid-portion terconnecting the cams to cyclically change their phase relation, the cams being shaped to cooperate with said gearing to move said guide with a cyclic non-uniform motion which is slower a An wind the rayon into a cake composed of inter-. crossing layers of non-uniform angular relation and having a substantially cylindrical mid-portionand convexly rounded end portions of radii less than the thickness of the mid-portion of the cake whereby to provide a cake which is uniformly pervious throughout to treating fluids.

3. In a rayon winding apparatus the combination with arotatably mounted drum and a guide movably mounted with respect to the drum, of an ,90 inverse harmonic cam operatively connected to said guide to move it longitudinally of the drum over a range less than the length of the drum,

a second inverse harmonic cam cooperating with the first-named cam to extend the range of ac: tion of the guide, and means cooperating witlf said cams to change their phase relations and wind the rayon in angularly disposed intercrossing layers into a uniformly pervious cake having a substantially cylindrical mid-portion and convexly rounded self-supporting end portions.

v 4. In a rayon winding apparatus, the combination of a rotatably mounted drum havinga foraminous winding .surface; a winding guide mounted for movement longitudinally of the drum, primary and secondary cams each opera- .tively connected to the guide to move it cyclically with respect to the drum, and phase-changing mechanism 'associated with said cams cooperating therewith to impart to the guide a non-uniform motion which is slower at its mid-portion than at its ends and thereby to wind the rayon into a cake composed'of angularly intercrossing layers disposed in non-uniform angular relation and having a substantially cylindrical mid-por- .tion and convexly rounded end portions the radii of which are less than that of the mid-portion and whose edges are disposed with [respect to the marginal foramina to provide a cake which is uniformly pervious throughout. Y

5. In a rayon winding apparatus the combination of a rotatably mounted drum having a foraminous winding surface, a guide mounted for movement longitudinally of the drum, and mechanism for winding the rayon angularly on the drum compris' g an inverse harmonic cam operatively connected to the guide for traversing it over a distance less than the, length of the drum,-

. and a'second inverse harmonic cam operatively connected to the guide to extend the range'of travel of the guide, and gearing associated with said cams to change their phase relation and. shift the guide in a cyclic non-uniform travel which is slower at the mid-portion than at the ends of travel to wind the rayon into a uniformly pervious cake composed of angularly intercross- 3 ing layers disposed in non-uniform-relation' and having a substantially cylindrical mid-portion and convexly'rounded self-supporting end portions the edges of which are disposed beyond the marginal foramina,

6. In a rayon winding apparatus the combination with a, rotatiyely mounted drum and'a guidej member mounted for movement longitudinally of the drum, of guide-member actuating means comprising two cams. operatively connected to said guide, and mechanism associated withsaid cams progressively changing their phase relatign to actuatethe guide with a cyclic non-uniform motion slower in travel at the mid-portionthan 150 the mid-portion of the travel than at its ends 80 at the ends to wind rayon upon said drum in angularly intercrossing layers into a cake having a substantially cylindrical mid-portion and convexly rounded end portions, the cake being uniformly'pervious throughout.

7. In a rayon winding device, a drum having a foraminous mid-portion, a guide mounted for reciprocation longitudinally of said drum surface for winding rayon yarn upon. the drum, and reciprocating means connected to said guide including a rocker arm, cam mechanism actuating said rocker arm, and driving mechanism actuat- WILLIAM F. RICHTER. 

